Cooking apparatus and method with product recognition

ABSTRACT

Cooking apparatus having first and second platens with product recognition. A positioning mechanism moves the second platen toward the first. A detector senses the second platen making contact with a food product disposed on the first platen and provides a signal. A controller uses the signal to measure the travel distance of the second platen. The product thickness is a function of the travel distance, which is used to select a cooking procedure for the food product. The controller then executes the selected cooking procedure to cook the food product. The detector can include a micro switch, proximity sensor, touch sensor, strain sensor, thermal sensor, optical sensor, sonar sensor or positioning load change sensor.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/662,041, filed on Mar. 15, 2005 and is acontinuation-in-part of U.S. patent application Ser. No. 11/070,348,filed on Mar. 2, 2005, which application claims the benefit of U.S.Provisional Patent Application Ser. No. 60/549,233, filed on Mar. 2,2004.

FIELD OF THE INVENTION

This invention relates to a cooking apparatus and method based on foodproduct thickness and/or recognition thereof.

BACKGROUND OF THE INVENTION

Cooking apparatus that includes two surfaces generally cooks bycontacting opposed sides of a food product. Cooking apparatus of thistype has been used in a variety of cooker styles. For example, a clamgrill uses a lower platen and an upper platen that is moveable towardand away from the lower platen. Examples of clam grills are disclosed inU.S. Pat. Nos. 6,079,321 and Re 32,994. Another style is a toaster inwhich one surface is a platen and the other surface is a conveyor belt.The conveyor belt and the platen can be either horizontal, vertical orat an angle therebetween. Examples of toasters are disclosed in U.S.Pat. Nos. 6,201,218 and 6,281,478.

These known cooking apparatuses generally include a motion mechanismthat either manually or automatically moves one platen toward anotheruntil opposed sides of the food product are contacted by the platens.For example, the clam grill disclosed in U.S. Pat. No. 6,079,321automatically controls the motion based on a set of parameters that mustbe input to a controller for each type of food product. These parametersinclude a preset gap distance, which is the cooking distance between thetwo platens to accommodate food products of different thicknesses. Thesegap distances are set by manually inputting the preset gap distancesetting into the grill control and assigning the setting to a gap buttonon the user interface control along with a cooking time. This set ofcooking parameters (gap distance and cooking time) must be preselectedbefore placing the food product on the grill surface.

The clam grill operator must also input the type of food product beingcooked so that the controller uses the parameter set for that foodproduct. Should the operator inadvertently input the wrong type, theupper platen may not contact the food product or may put too muchpressure on the food product. Since the parameter set also includes thecook time for the food product type, the food product could beundercooked or over cooked. Thus, there is opportunity for human errorat the time of entry of the preset gap distances as well as at the timeof selecting the type of food being cooked.

There is a need for a cooking apparatus that automatically controls therelative motion of the two platens in a manner that avoids user error.

SUMMARY OF THE INVENTION

The cooking apparatus of the present invention comprises a first platenand a second platen disposed in spaced apart relationship to oneanother. A positioning mechanism moves the second platen toward and/oraway from the first platen. A controller is responsive to the secondplaten making contact with a food product disposed on the first platenwhen the second platen is moved by the positioning mechanism toward thefirst platen to recognize the food product.

In one embodiment of the cooking apparatus of the present invention, thecontroller determines a cook time for the food product based on therecognized thickness and a user entered category of the food product.

In another embodiment of the cooking apparatus of the present invention,the cook time is determined by the product of the square of the productthickness multiplied by a constant related to the food category.

In another embodiment of the cooking apparatus of the present invention,the recognized thickness is derived from a travel distance of the secondplaten.

In another embodiment of the cooking apparatus of the present invention,the travel distance is derived from a predetermined reference point anda non-cooking position of the second platen.

In another embodiment of the cooking apparatus of the present invention,the cooking apparatus further comprises a detector disposed to provide asignal as the second platen, when moved by the positioning mechanismtoward the first platen, makes contact with the food product disposed onthe first platen. The controller responds to the signal, therebyrecognizing the food product.

In another embodiment of the cooking apparatus of the present invention,the controller executes a cooking procedure to cook one or more foodproducts disposed on a grill surface of the first platen with the secondplaten having a first cooking position based on a first thickness of thefood products. The controller during the cooking procedure raises andlowers the positioning mechanism and/or the second platen.

In another embodiment of the cooking apparatus of the present invention,the controller executes a product thickness change control during thecooking procedure to determine a second cooking position based on asecond thickness thereof and to lower the positioning mechanism and/orthe second platen to the second cooking position.

In another embodiment of the cooking apparatus of the present invention,the cooking apparatus further comprises a detector disposed to provide asignal as the second platen makes contact with the food products. Thecontroller responds to a first indication and a second indication of thesignal to move the positioning mechanism and/or the second platen intothe first and second positions, respectively.

In another embodiment of the cooking apparatus of the present invention,the product thickness change control causes the controller to raise thepositioning mechanism and/or the second platen from the first cookingposition and, based on the second indication of the signal, causes thecontroller to move the positioning mechanism and/or the second platen tothe second cooking position.

In another embodiment of the cooking apparatus of the present invention,the raising and lowering is done in a manner to release moisture fromthe food products.

In another embodiment of the cooking apparatus of the present invention,the controller executes a moisture release control during the cookingprocedure that raises the positioning mechanism and/or the second platento a predetermined distance above a grill surface of the first platen,holds the second platen at the predetermined distance for a time T, andwhen the time T expires, lowers the positioning mechanism and/or thesecond platen toward the first platen.

The method of the present invention cooks a food product with a cookingapparatus that has first and second platens. The method comprises movingthe second platen toward the first platen and in response to the secondplaten making contact with a food product disposed on the first platen,recognizing the food product due to its thickness.

In one embodiment of the method of the present invention, based on therecognized food product and a user entered food category of the foodproduct, a cook time for the food product is determined.

In another embodiment of the method of the present invention, the cooktime is determined by the product of the square of the product thicknessmultiplied by a constant related to the food category.

In another embodiment of the method of the present invention, thethickness is derived from a travel distance of the second platen.

In another embodiment of the method of the present invention, the traveldistance is derived from a predetermined reference point and anon-cooking position of the second platen.

In another embodiment of the method of the present invention, the methodfurther comprises providing a signal as the second platen, when moved bythe positioning mechanism toward the first platen, makes contact withthe food product. The recognizing step uses the signal to recognize thefood product due to its thickness.

In another embodiment of the method of the present invention, the methodfurther comprises, based on the thickness, moving the second platen to afirst cooking position, executing a cooking procedure to cook the foodproduct and, during the cooking procedure, raising and lowering thesecond platen.

In another embodiment of the method of the present invention, the methodfurther comprises determining a second cooking position based on asecond thickness of the food product and moving the second platen to thesecond cooking position.

In another embodiment of the method of the present invention, the methodfurther comprises providing a signal as the second platen makes contactwith the food product; and in response to a first indication and asecond indication of the signal to move the second platen into the firstand second positions, respectively.

In another embodiment of the method of the present invention, the methodfurther comprises raising the second platen from the first cookingposition and, based on the second indication of the signal, moving thesecond platen to the second cooking position.

In another embodiment of the method of the present invention, theraising and lowering is done in a manner to release moisture from thefood products.

In another embodiment of the method of the present invention, during thecooking procedure the second platen is raised to a predetermineddistance above a grill surface of the first platen. The second platen isheld at the predetermined distance for a time T. When the time Texpires, the second platen is lowered toward the first platen.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, advantages and features of the presentinvention will be understood by reference to the following specificationin conjunction with the accompanying drawings, in which like referencecharacters denote like elements of structure and:

FIG. 1 is a perspective view of one embodiment of a two-surfaced cookingapparatus of the present invention;

FIG. 2 is a side view of the two-surfaced cooking apparatus of FIG. 1;

FIG. 3 is a rear view of the two-surfaced cooking apparatus of FIG. 1;

FIG. 4 is a top view of the upper platen assembly of the two-surfacedcooking apparatus of FIG. 1;

FIG. 5 is a cross-sectional view along line 5 of FIG. 4;

FIG. 6 is a view of detail B of FIG. 5;

FIG. 7 is a block diagram of an alternate embodiment of the detector ofthe two-surfaced cooking apparatus of the present invention;

FIG. 8 is a side view of a portion of the two-surfaced cooking apparatusof FIG. 1 that depicts another embodiment of the detector;

FIG. 9 is a side view of a portion of the two-surfaced cooking apparatusof FIG. 1 that depicts another embodiment of the detector;

FIG. 10 is a side view of a portion of the two-surfaced cookingapparatus of FIG. 1 that depicts another embodiment of the detector;

FIG. 11 is a side view of a portion of the two-surfaced cookingapparatus of FIG. 1 that depicts another embodiment of the detector;

FIG. 12 is a block diagram of a preferred embodiment of the controllerof the cooking apparatus of FIG. 1;

FIG. 13 is a flow diagram for the product recognition program of thecontroller of FIG. 12;

FIG. 14 is a flow diagram of another embodiment of a program that can beused with the cooking apparatus of FIG. 1;

FIG. 15 is a flow diagram of a moisture release control of the presentinvention;

FIG. 16 is a graph of temperature vs. time for a cook procedure;

FIG. 17 is a flow diagram of a cook time compensation program of thepresent invention;

FIG. 18 is a flow diagram of another embodiment of a product recognitionprogram of the present invention; and

FIG. 19 is a flow diagram of a product thickness change control of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

It is contemplated that the present invention can be used in variousstyles of two-surfaced cooking apparatus, for example, two-sided contacttoasting, clam grills and the like. However, by way of example andcompleteness of description, the present invention will be describedherein in a clam grill embodiment.

Referring to FIGS. 1-3, a two-surfaced cooking apparatus of the presentinvention comprises a support structure 22 to which a lower (first)cooking platen 24 is horizontally mounted. Lower platen 24 has a smoothlevel cooking surface 26 on its upper side. Lower platen 24 is heated tocooking temperature by gas or electric means via heating elements 28 orequivalent gas burners.

A platen assembly 30 and a platen assembly 31 are movably mounted to therear of support structure 22 by a positioning mechanism 40 and apositioning mechanism 41, respectively. As platen assembly 30 and platenassembly 31 are substantially identical, only platen assembly 30 will bedescribed in detail. Platen assembly 30 comprises an upper (second)cooking platen 32 that has a surface 34. Preferably, surface 34 isheated to cooking temperature by heating elements (not shown) mountedwithin a casing 36. Upper platen 32 is either smaller than orequivalently sized to lower cooking platen 24. A handle 38 mounted onthe front side of platen assembly 30 for manual manipulation thereof.Cooking apparatus 20 may have one or more upper platen assemblies.Although two upper platen assemblies are shown, other embodiments mayhave one or more than two upper platen assemblies. In a preferredembodiment, two or more separate upper platen assemblies are mountedover a single lower platen, allowing for greater flexibility for thecook/operator. Although lower platen 24 is shown as a single platen, itcan be two or more platens in alternate embodiments.

Cooking apparatus 20 further includes a controller 62 (shown in FIG. 2)that is interconnected with heaters 28, a motor controller 64, a userinterface 68 and one or two activation buttons 60. Controller 62controls the cook cycle of cooking apparatus 20 and in so doing controlsmotor controller 64 and positioning mechanism 40 that imparts motion toplaten assembly 30. User interface 68 includes a display and varioususer controls. Activation buttons 60 are disposed on the front ofcooking apparatus for user control of platen assembly 30. Activationbuttons 61 are disposed on the front of cooking apparatus for usercontrol of platen assembly 31.

As positioning mechanism 40 and positioning mechanism 41 aresubstantially identical, only positioning mechanism 40 will be describedin detail. Positioning mechanism 40 facilitates two distinct motions byplaten assembly 30 between an uppermost or non-cooking position (seeFIG. 3) to a cooking position. In FIGS. 1-3, platen assembly 30 is inthe non-cooking position and platen assembly 31 is in the cookingposition. In this embodiment, positioning mechanism 40 includes a linearactuator 42 that is linked to two vertical reciprocating shafts 44 by anactuator cross bar linkage 46. Actuator cross bar linkage 46 is clampedto vertical reciprocating shafts 44, which run through linear motionbearings 48. Vertical reciprocating shafts 44 are affixed to armpivot/stop heads 50. A cantilever beam 52 runs through arm pivot/stopheads 50 through rotational pivot bearings 54. When platen assembly 30is in its uppermost rotational position, linear actuator 42 is extendedto its maximum position, vertical reciprocating shafts 44 and armpivot/stop heads 50 are extended upward and to a position which forcesthe back end of cantilever beam 52 to contact rotational bearings 54. Inthis position, platen assembly 30 is at a predetermined angle in a rangeof about 45 degrees to about 60 degrees from the horizontal.

Positioning mechanism 40 further comprises a drive motor 56 and positionsensor switches 58 (FIG. 3). Drive motor 56 is interconnected with motorcontroller 64. A pulse encoder 66 is associated with motor 56 andprovides a pulse train to controller 62 when motor 56 is being driven.Position switches 58 are mounted on reciprocating shafts 44 to provideposition information to controller 62. In alternate embodiments,position switches 58 may be eliminated.

Prior to a cook cycle, platen assembly 30 is in its non-cookingposition. In response to user activation of activation buttons 60,controller 62 initiates a cook cycle by controlling motor controller 64to drive motor 56 to cause positioning mechanism 40 to move platenassembly 30 from the non-cooking position to a cooking position. Forexample, platen assembly 31 is shown in the cooking position.

Positioning mechanism 40 causes platen assembly 30 to descend bothvertically and through an arc caused by the cantilever weight of platenassembly 30 maintaining contact between rotational bearings 54 and theback of cantilever beam 52. When cantilever beam 52 and platen assembly30 become parallel with lower platen 24, the stop portion of armpivot/stop head 50 stops the rotational motion of cantilever beam 52causing purely vertical motion of platen assembly 30 from this point andfurther down toward surface 26 of lower platen 24. When upper platen 32makes contact with a food product 72, controller 62 responds by bringingupper platen 32 to an initial cooking position and initiating a cookprocedure. During the cook procedure upper platen 32 may be moved basedon the requirements of the cook procedure. For example, upper platen 32may be moved due to changed food product thickness (loss of grease orwater) or for applying more or less pressure to the food product atdifferent times during the cook procedure.

When the cook procedure is completed, controller 62 controls motorcontroller 64 to drive linear actuator 42 to move platen assembly 30vertically upward from the cooking position to the non-cooking position.The cantilever weight of upper platen 32 maintains contact between armpivot/stop head 50 until the back of cantilever beam 52 makes contactwith rotational pivot bearing 54. This movement ensures that platenassembly 30 is constantly parallel to lower platen 24 during this stageof upper platen travel. Once cantilever beam 52 makes contact withrotational pivot bearing 54 the vertical motion is changed to rotationalmotion to a point where platen assembly 30 is rotated through thepredetermined angle to the non-cooking position. Controller 60 causes anaudible signal to be sounded (e.g., about two seconds) prior to thestart of upward movement of platen assembly 30 to alert the operator ofimpending upper platen movement.

The present invention provides a detector that provides a trigger signalas upper platen 32 makes contact with food product 72. Controller 62responds to the trigger signal to control motor controller 64 to causepositioning mechanism 40 to bring upper platen 32 to the initial cookingposition. At this time, controller 62 begins the cooking procedure. Thedetector is shown herein in several different embodiments.

Referring to FIGS. 4-6, a detector 70 is disposed or attached tocantilever beam 52 of positioning mechanism 40. When upper platen 32stops moving because it makes contact with a food product, its motioncomes to a stop or continues to move based on the cooking parametersinputted into controller 62. Positioning mechanism 40 continues to movecantilever beam 52 vertically downward toward casing 36. Detector 70senses a small change in the distance between cantilever beam 52 andcasing 36 to provide the trigger signal that triggers positioningmechanism 40 to bring upper platen 32 to the initial cooking position.

Referring to FIG. 6, a fastener 74 fastens cantilever beam 52 to casing36. Fastener 74 is mounted in cantilever beam 52 in a manner that allowsit to float vertically when upper platen 32 is in contact with foodproduct 72. Thus, when upper platen 32 makes contact with food product72, upper platen 32 stops but cantilever beam 52 continues downwardlydue to the floating action of fastener 74.

In this embodiment, detector 70 is preferably a proximity sensor, forexample, model PRX+4400, available from Hermetic Switch Inc. Detector 70may alternatively be a micro-switch, for example, model E47BM530,available from Eaton/Cutler Hammer.

Detector 70 may alternatively be a touch sensor including dielectricsensing as well as piezo-electric pressure sensing. For example, thetouch sensor may be model T107-A4E-073, available from Piezo Systems,Inc.

Detector 70 may alternatively be a sonar sensor that is attached toupper platen 32, lower platen 24 or support structure 22 to detect asound change due to upper platen 32 contacting the food product. Forexample, the sonar sensor may be model EFR-RTQB40KS, available fromPanasonic.

Although detector 70 is shown in a specific location, detector 70 can bepositioned at any suitable location of cantilever beam 52 that permitsdetection of upper platen 32 contacting food product 72. For example,these locations include the front, back, either side, middle or other.In an alternate embodiment, detector 70 may include multiple detectorspositioned at different locations.

Referring to FIG. 7, a detector 80 monitors the motor current of drivemotor 56. When upper platen 32 contacts food product 72, the motorcurrent changes. Detector 80 detects this current change and signalsmotor controller 64. Detector 80 can either be separate from motorcontroller 64 or integral with motor controller 64. If integral, thereis no need for detector 80 to signal motor controller 64. Detector 80includes a current sensing resistor 82 (or other circuit for measuringcurrent) connected in the motor current circuit. Detector 80 alsoincludes a current change detection circuit 84 that provides the triggersignal to motor controller 64 when current change detection circuit 84detects a change in motor current indicative of upper platen 32 makingcontact with food product 72. The trigger signal is supplied tocontroller 62.

Referring to FIG. 8, a detector 90 comprises a strain sensor attached ina location that detects a change in load after upper platen comeshorizontal and when the weight of upper platen 32 is reduced by restingon food product 72. When detector 90 detects this change in strain, itprovides a trigger signal to controller 62. Controller 62 then controlsmotor controller 64 to cause positioning mechanism 40 to bring upperplaten 32 to the cooking position. Like detector 80, detector 90 mayinclude a detection circuit (not shown) to detect when a change in themonitored strain signal is indicative of upper platen 32 making contactwith food product 72.

Referring to FIG. 9, a detector 100 includes an optical transmitter 102and an optical receiver 104 that are positioned to the rear and front,respectively, of cooking apparatus 20. Optical transmitter 102 providesan optical beam 106 from back to front at a level that will beinterrupted by upper platen 32 at about the time it contacts the foodproduct. Optical receiver 104 receives beam 106 and provides a triggersignal when upper platen 32 interrupts beam 106. Controller 62 uses thetrigger signal to bring upper platen 32 to the cooking position. Opticalbeam 106 may be visible light or invisible, e.g., infrared.

Referring to FIG. 10, alternatively an optical detector 110 is mountedto cantilever beam 52. Thus, an optical transmitter 112 and an opticalreceiver 114 are mounted and spaced from one another by a gap such thata light beam emitted by optical transmitter 112 traverses the gap and isreceived by optical receiver 114. A shutter 116 is mounted on casing 36.When upper platen 32 is not in contact with the food product, shutter116 is outside the gap between optical transmitter 112 and opticalreceiver 114. When upper platen 32 slows or stops, it contacts the foodproduct, while cantilever beam 52 continues to move toward casing 36such that shutter 116 enters the gap and interrupts the light beam.Optical receiver 114 responds by providing a trigger signal tocontroller 62. Controller 62 uses the trigger signal to bring upperplaten 32 to the cooking position.

Referring to FIG. 11, a detector 120 comprises a plurality oftemperature sensors 122 disposed at various locations in upper platen32. Temperature sensors 122 provide temperature signals to controller62. When the operator starts a cooking cycle, controller 62 monitors thetemperature sensor signals. When controller 62, based on the temperaturesensor signals, determines that a given temperature drop in a specifiedamount of time has occurred, it controls motor controller 64 to causepositioning mechanism 40 to bring upper platen 32 to the cookingposition.

It will be apparent to those skilled in the art that detection circuitscan be used in any of the detectors 70, 80, 90, 100, 110 and 120 todiscriminate the trigger signal from noise.

Referring to FIG. 12, controller 62 includes a processor 130interconnected by a bus 136 with an input/output (I/O) module 132 and amemory 134. Memory 134 may be any suitable memory that includes, randomaccess memory (RAM), read only memory (ROM), flash or other memory typesor any combination thereof. Processor 130 may be any suitable processorthat is capable of running programs that execute cook cycles includingcook procedures. I/O module 132, contains interfaces to each of aplurality of input/output devices, including user interface 68, pulseencoder 66, detector 70, 80, 90, 100, 110 or 120, heater elements 28,motor controller 64 and any other input/output devices included in acooking apparatus.

Memory 134 stores a plurality of programs and parameter data including acook cycle program 140, a product thickness list 144, a set of cookprocedures 146 and a distance counter 148. Cook procedures 146 include aset of cook procedures for use by cooking apparatus 20. For example,cook procedures 146 include a cook procedure for bacon, a cook procedurefor a hamburger, a cook procedure for a chicken patty and so on.

A cook procedure, for example, may simply be a cook time or may alsoinclude temperatures for different portions of the cook time, differentpressures and/or gap distances for upper platen 32 at different portionsof the cook time.

Cook cycle program 140 includes a product recognition program 142 thatrecognizes a food product 72 currently on the grill surface 26 of lowerplaten 24 of FIGS. 1-6. This recognition is based on a travel distanceof upper platen 32 measured between a reference point to a position atwhich it makes contact with food product 72. When cooking apparatus 20is first started from a cold start, a preheat mode is used before foodproduct 72 can be placed on lower platen 24. In the preheat mode, platenassembly 30 is lowered until it comes to a stop on lower platen 24 andengages detector 70. The heaters for lower platen 24 and upper platen 32are turned on and the platen surfaces are heated to their presettemperatures.

After upper platen 32 has been preheated, platen assembly 30 is raisedto its upper most non-cooking position to allow the operator to safelyplace food product 72 on lower platen 24. As platen assembly 30 beginsto rise,

cantilever beam 52 reaches the end of the float distance, detector 70 isreleased from its detected state and generates a trigger signal thatcontroller 62 uses as the reference point. This reference pointrepresents a reference count value, e.g., zero, of surface 26 of lowerplaten 24.

As platen assembly 30 continues to rise, encoder pulses are counted fromthe reference point to the non-cooking position. Controller 62 recordsthe total count value from the reference point to the upper mostnon-cooking position, which represents a predetermined reference countvalue. After food product 72 is placed on lower platen 24, platenassembly 30 is again lowered. When upper platen 32 contacts food product72, detector 70 generates a trigger signal, which controller 62 uses torecord the encoder pulse count value at the time of contact with foodproduct 72. The product thickness is represented by the differencebetween the pulse count value at the food product contact time and thepredetermined reference count value.

It will be apparent to those skilled in the art that other techniques ofmeasuring the travel distance can be used. For example, the traveldistance can be measured by the time that elapses between currenttriggered count value and the reference point value. The elapsed time,for example, is measured by counting pulses from a timing source, suchas a clock. This elapsed time or pulse count is recorded in distancecounter 148. Product recognition program 142 uses distance to recognizea product thickness and uses the recognized product thickness to selecta product cook procedure from cook procedures 146 that matches theproduct thickness.

Referring to FIG. 13, cook cycle program 140 begins at step 170 bystarting a cook cycle. Step 170 is performed in response to the operatoractivating activation button 60. At step 172 cooking apparatus 20 isinitialized. For example, heating elements 28 are turned on and otherpreliminary operations (not germane to the present invention) areperformed. Once cooking apparatus 20 is initialized, product recognitionprogram 142 is executed.

At step 174, distance counter 148 is initialized to a reference value,e.g., zero. At step 176 motor 56 is started. Processor 130 provides oneor more command signals via I/O module 132 to motor controller 64 toprovide drive current to motor 56. This causes positioning mechanism 40to lower upper platen 32 from its non-cooking position. At step 178,there is a determination of whether a trigger signal has been receivedfrom the detector (70, 80, 110, 110 or 120). If not, at step 180 it isdetermined if an encoder pulse has been received. If not, controlreturns to step 178. If step 180 determines that an encoder pulse hasbeen received, at step 182 distance counter 148 is incremented. It willbe appreciated by those skilled in the art that distance counter 148could also be decremented from the reference value. Control then returnsto step 178 and steps 178, 180 and 182 iterate until step 178 detects atrigger signal.

If step 178 determines that a trigger pulse has arrived, at step 184 aproduct cook procedure is selected from cook procedures 146 based on thecount value of distance counter 148 as of the arrival of the triggerpulse. At step 186 the selected cook program is executed. When step 186is completed at step 188 upper platen 32 is returned to its non-cookingposition. To perform step 188, processor 130 provides one or morecommand signals via I/O module 132 to motor controller 64 to providedrive current to motor 56. This causes positioning mechanism 40 to raiseupper platen 32 from its cooking position to its non-cooking position.

More specifically, step 184 matches the trigger count value of distancecounter 148 with count values for different product thicknesses for thefood products stored in product thickness list 144. That is, each countvalue stored in product thickness list 144 is indicative of acorresponding product thickness of the food product of a correspondingcook procedure. If the trigger count value of distance counter 148 isin-between two of the count values in product thickness list 144, thecount value closest to the trigger count value is used to select acorresponding cook procedure from cook procedures 146.

In an alternate embodiment, product thickness list 144 stores athickness window for the product of each cook procedure. The thicknesswindow is defined by an upper and a lower count value plus or minus atolerance. The thickness window within which the trigger count valuefalls is used to select the corresponding cook procedure from cookprocedures 146. If the trigger count value falls between two thicknesswindows, the closest thickness window is used. For example, thepredetermined thickness could be 0.500±0.060 inch.

During a programming operation, product thickness list 144 and productcook procedures 146 are populated with respective thickness count valuesand cook procedures for the food products that are to be cooked withfood cooking apparatus 20. The thickness count values and cookprocedures can be entered, for example, via a keyboard or other inputdevice (not shown) either via a wired connection or a wireless link.

Referring to FIG. 14, an alternate embodiment of the cook cycle programresponds to the trigger signal to execute a cook procedure that ispre-selected by the operator, for example, from user interface 68. Acook cycle program 200 begins at step 202 by starting a cook cycle. Step202 is performed in response to the operator activating activationbutton 60. At step 204 cooking apparatus 20 is initialized. For example,heating elements 28 are turned on and other preliminary operations (notgermane to the present invention) are performed.

At step 206 motor 56 is started. Processor 130 provides one or morecommand signals via I/O module 132 to motor controller 64 to providedrive current to motor 56. This causes positioning mechanism 40 to lowerupper platen 32 from its non-cooking position. At step 208, there is adetermination of whether a trigger signal has been received from thedetector (70, 80, 110, 110 or 120). If not, then step 208 repeats. Ifstep 208 determines that a trigger signal has been received, then atstep 208 the pre-selected cook procedure is executed. When thepre-selected cook procedure has been completed, then at step 212 upperplaten 32 is returned to its non-cooking position. Processor 130provides one or more command signals via I/O module 132 to motorcontroller 64 to provide drive current to motor 56. This causespositioning mechanism 40 to raise upper platen 32 from its cookingposition to its non-cooking position.

The cooking program or procedure for any food product can include astage or multiple stages that causes the upper platen to raise from thefood product a programmed distance and time duration to releasemoisture.

Referring to FIG. 15, a moisture release feature of the presentinvention comprises a moisture release control 360 that can be executedduring a cooking procedure and executed by controller 62. Moisturerelease control 360 at step 362 raises upper platen 32 to apredetermined distance above the food product. As upper platen 32 rises,the trigger signal changes from on to off. Controller 62 maintains upperplaten 32 in this location for a predetermined time T selected formoisture release. When the predetermined time T expires, step 364 lowersupper platen 32 until the trigger signal is detected. That is, upperplaten 32 makes contact with the food product. This procedure can berepeated as many times as desired for a given food product.

During the cooking process the platen temperature profiles/energyconsumption is monitored by controller 62. This data is compared toreference data and used to adjust the cooking time to compensate fordifferences in quantity, density, food starting temperature(frozen/unfrozen) and the like. Controller 62 then compensates thecooking time longer or shorter based on the temperature profile for theparticular product thickness for better non-full or partial load cookingoperations and improved product quality. Controller 62 can also use thetemperature profile/energy consumption and product thickness todetermine the proper cooking program for the energy over time to selectfood product (e.g., more dense/less dense products and/or frozen/thawedproducts) being cooked.

The temperature drop during the cooking cycle or part of the cookingcycle, together with the information of the heaters turn-on and turn-offpattern will also give information regarding the cooking product thermalload. The thermal load will change dependent on several variables suchas; quantity of food products, initial temperature of products, watercontent of products, density of food products.

Referring to FIG. 16, curve 370 is a reference plot of temperature ofone of the platens (e.g., lower platen 24) versus time for a cookingprocedure for a reference quantity of a particular food product. At thebeginning of the cook cycle, lower platen 24 and upper platen 32 arepreheated to a set temperature Tset for the reference quantity of theparticular food products. Curve 370 is at Tset at time t0. At this time,the reference quantity of food products has been placed on lower platen24 and the operator is activating motion of upper platen 32 toward thefood products. The temperature of lower platen 24 begins to drop. Bytime t1, upper platen has come into contact with the food products. Attime t2, the temperature of lower platen 24 reaches a minimumtemperature Tmin and begins to rise. By time t4, the temperature oflower platen has returned to the set temperature. Curve 370 is for asimple cooking procedure in which the reference quantity of the foodproducts are cooked at a constant set temperature Tset with no moisturerelease or other functions that cause upper platen to move out ofcontact with the food products. It will be apparent to those skilled inthe art that cooking procedures can also involve such movements of upperplaten and different set temperatures for various stages of the cookingprocedure. Curve 370 constitutes a reference temperature curve for thecooking procedure for the reference quantity of the particular foodproducts. Similar curves are generated for cooking procedures for otherfood products. Data from these curves is stored for use during theactual cooking of the food products. For example, this data comprisesthe temperatures of curve 370 taken at one or more desired sample timesbetween to and t4.

Referring to FIG. 17, a cook time compensation program 380 is executedeither as part of product recognition program 142 or in other cookingapplications. By way of example, cook time compensation program 380 willbe described as being executed in conjunction with product thicknessrecognition program 142. Cook time compensation program 380 begins withstep 382 with the initiation of a cook procedure for the particular foodproducts. Lower and upper platens 24 and 32 are preheated to the settemperature Tset. Upper platen 32 is then raised and the operator placesa current quantity of the particular food products on lower platen 24.The operator also causes upper platen to begin moving toward the foodproducts. During the period from t0 to t4 one or more temperaturesamples are taken at step 384. Step 386 compares these temperaturesamples with the reference temperature samples taken from curve 370. Insome embodiments, the comparison will only consider the minimum Tmin ofthe current food products and the Tmin of the reference food products.Step 386 determines if any of the current temperature samples deviateabove or below the reference temperature samples by more than apredetermined amount. If not, cook time compensation program 380 ends at390. That is, the quantity of food products being cooked issubstantially equal to the reference quantity of food products. If thereis a deviation by more than a predetermined amount, step 388 adjusts thecooking time. For example, if the deviation is above the referencetemperature, the cooking time is shortened. If the deviation is belowthe reference temperature, the cooking time is lengthened. Cook timecompensation program 380 then ends at 390.

As described above, product recognition program 142 selects a cookprocedure based on a count value that represents the food productthickness or height. According to the present invention, an alternateproduct recognition program 400 uses the product thickness or height anda user entered food category to determine a cook time for the product.

Referring to FIG. 18, a product recognition program 400 begins at step402 by posting or recording the product thickness or height as or basedon the count value determined by steps 170-182 of FIG. 13. Step 404determines the food category entered by a user or operator of cookingapparatus 20. For example, buttons for different food categories, suchas beef, chicken, vegetable and other categories, can be provided on theuser interface 68. When placing the food product on the lower platen 24,the user selects a food category. Step 406 gets a constant k that isbased on the food product category determined by step 404. Step 408determines a cook time based on the product thickness and the enteredfood category. The cook time is calculated based on the relationship ofcook time equals (product thickness)²×k. Step 410 uses the cook time tocook the food product.

Using user interface 68, the operator can manually select betweencooking products using product recognition program 142 or productrecognition program 400.

Referring to FIG. 19, a product thickness change control 420 is usedduring a cook procedure to detect changes (expanding or shrinking) inproduct thickness that occur during cooking. Product thickness changecontrol 420 begins at step 422 with the start of the cook procedure.Step 424 waits for a predetermined time (e.g., 40% of the cook time) toexpire and then raises upper platen 32 by a predetermined amount (e.g.,0.25 inch for a hamburger patty). Step 426 determines if there has beena change in state of the trigger signal. If not, step 432 is performed.If yes, step 428 determines the position of upper platen 32 at the timeof state change of the trigger signal. For example, the pulse count ofthe distance counter (see steps 180 and 182 in FIG. 13) would bedecremented if the state changes when upper platen 32 is raised. Step430 then readjusts the position of the upper platen based on the newthickness of the food product. Step 432 repeats steps 424, 426, 428 and430 as desired during the cook procedure.

In any of the processes described above, controller 62 can be programmedto maintain either a full weight or a partial weight of upper platen 32on the food product during the cooking program.

The present invention having been thus described with particularreference to the preferred forms thereof, it will be obvious thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of the present invention as defined in theappended claims.

1. A cooking apparatus comprising: a first platen and a second platendisposed in spaced apart relationship to one another; a positioningmechanism that moves said second platen toward and/or away from saidfirst platen; a controller responsive to said second platen makingcontact with a food product disposed on said first platen when saidsecond platen is moved by said positioning mechanism toward said firstplaten to recognize said food product and to determine a cook time forsaid food product based on a user entered category of said food product.2. The cooking apparatus of claim 1, wherein said recognized thicknessis derived from a travel distance of said second platen.
 3. The cookingapparatus of claim 2, wherein said travel distance is derived from apredetermined reference point and a non-cooking position of said secondplaten.
 4. The cooking apparatus of claim 1, further comprising adetector disposed to provide a signal as said second platen, when movedby said positioning mechanism toward said first platen, makes contactwith said food product disposed on said first platen, and wherein saidcontroller responds to said signal, thereby recognizing said foodproduct.
 5. The cooking apparatus of claim 1, wherein said cook time isdetermined by the product of the square of said product thicknessmultiplied by a constant related to said food category.
 6. A method forcooking a food product in a cooking apparatus that has first and secondplatens, said method comprising: moving said second platen toward saidfirst platen; in response to said second platen making contact with afood product disposed on said first platen, recognizing said foodproduct due to its thickness; and based on said recognized food productand a user entered food category of said food product, determining acook time for said food product.
 7. The method of claim 6, wherein saidthickness is derived from a travel distance of said second platen. 8.The method of claim 7, wherein said travel distance is derived from apredetermined reference point and a non-cooking position of said secondplaten.
 9. The method of claim 6, further comprising: providing a signalas said second platen, when moved by said positioning mechanism towardsaid first platen, makes contact with said food product, and whereinsaid recognizing step uses said signal to recognize said food productdue to its thickness.
 10. The method of claim 6, wherein said cook timeis determined by the product of the square of said product thicknessmultiplied by a constant related to said food category.
 11. A cookingapparatus comprising: a first platen and a second platen disposed inspaced apart relationship to one another; a positioning mechanism thatmoves said second platen toward and/or away from said first platen; anda controller that executes a cooking procedure to cook one or more foodproducts disposed on a grill surface of said first platen with saidsecond platen having a first cooking position based on a first thicknessof said food products, and wherein said controller during said cookingprocedure raises and lowers said positioning mechanism and/or saidsecond platen.
 12. The cooking apparatus of claim 11, wherein saidcontroller executes a product thickness change control during saidcooking procedure to determine a second cooking position based on asecond thickness thereof and to lower said positioning mechanism and/orsaid second platen to said second cooking position.
 13. The cookingapparatus of claim 12, further comprising a detector disposed to providean signal as said second platen makes contact with said food products,and wherein said controller responds to a first indication and a secondindication of said signal to move said positioning mechanism and/or saidsecond platen into said first and second positions, respectively. 14.The cooking apparatus of claim 13, wherein said product thickness changecontrol causes said controller to raise said positioning mechanismand/or said second platen from said first cooking position and, based onsaid second indication of said signal, causes said controller to movesaid positioning mechanism and/or said second platen to said secondcooking position.
 16. The cooking apparatus of claim 11, wherein saidraising and lowering is done in a manner to release moisture from saidfood products.
 17. The cooking apparatus of claim 16, wherein saidcontroller executes a moisture release control during said cookingprocedure that raises said positioning mechanism and/or said secondplaten to a predetermined distance above a grill surface of said firstplaten, holds said second platen at said predetermined distance for atime T, and when said time T expires, lowers said positioning mechanismand/or said second platen toward said first platen.
 18. A method forcooking a food product in a cooking apparatus that has first and secondplatens, said method comprising: moving said second platen toward saidfirst platen; in response to said second platen making contact with saidfood product disposed on said first platen, recognizing said foodproduct due to a first thickness thereof; based on said first thickness,moving said second platen to a first cooking position; executing acooking procedure to cook said food product; and during said cookingprocedure, raising and lowering said second platen.
 19. The method ofclaim 18, further comprising: determining a second cooking positionbased on a second thickness of said food product; and moving said secondplaten to said second cooking position.
 20. The method of claim 19,further comprising: providing a signal as said second platen makescontact with said food product; and in response to a first indicationand a second indication of said signal to move said second platen intosaid first and second positions, respectively.
 21. The method of claim20, further comprising: raising said second platen from said firstcooking position; and based on said second indication of said signal,moving said second platen to said second cooking position.
 22. Themethod of claim 18, wherein said raising and lowering is done in amanner to release moisture from said food products.
 23. The cookingapparatus of claim 16, wherein during said cooking procedure said secondplaten is raised to a predetermined distance above a grill surface ofsaid first platen, wherein said second platen is held at saidpredetermined distance for a time T, and when said time T expires, saidsecond platen is lowered toward said first platen.